(a) Technical Field
The present disclosure relates to a stable power supply device for a high voltage battery system in a vehicle. More particularly, the present disclosure relates to a stable power supply device for a high voltage battery system, which uses a resistor of a temperature raising system for raising the temperature of a high voltage battery in a vehicle during precharging at an initial stage of ignition.
(b) Background Art
In general, a high voltage battery system configured with a high voltage battery and high voltage components (e.g., an inverter, a low voltage DC to DC converter (LDC), a full automatic temperature control (FATC), and the like) using the high voltage battery as a power source can be mounted in a “green” vehicle, such as a hybrid electric vehicle (HEV) or an electric vehicle (EV). The high voltage battery system requires stable power at an initial stage of ignition to drive the high voltage components. To this end, the high voltage battery system stably supplies power to the high voltage components, e.g., using a high voltage relay and a high capacity resistor.
However, when a problem occurs with the high voltage components, the high capacity resistor, or the like, may be damaged, which causes damage of an undesired component, thereby resulting in an increase in repair cost of the component.
FIG. 1 illustrates, as an example, a conventional high voltage battery system for a green vehicle. As shown in FIG. 1, a conventional high voltage battery system includes a high voltage battery 1, high voltage components (e.g., an inverter 2, an LDC 3 and an FATC 4) using the high voltage battery 1 as a power source, and high voltage relays 5, 6 and 7 and a high capacity resistor 8 for precharge, configured to supply stable power to the high voltage components 2, 3 and 4. The operation of each high voltage relay 5, 6 or 7 is controlled by a battery management system (BMS) 9.
In the high voltage battery system of FIG. 1, as the on/off of each high voltage relay 5, 6 or 7 is operated according to a relay sequence in initial ignition of the vehicle, the voltage of a capacitor in the high voltage component(s) (e.g., the inverter, the LDC or the FATC) is increased. In this state, the voltage of the capacitor is gradually increased by the high capacity resistor 8 for precharge, and the current value of the system is changed depending on a difference between the voltage of the battery and the capacitor voltage by the high capacitor resistor 8. For example, if the capacitor voltage increases, the current value of the system decreases.
As such, the high capacity resistor 8 for precharge in the high voltage battery system plays an important role to supply stable power in initial ignition of the vehicle. Therefore, when the high capacity resistor for precharge is damaged due to the occurrence of an error in the high voltage battery system, ignition of the vehicle becomes impossible.
Since a certain degree of power remains in the capacitor in the high voltage component(s), even after the ignition of the vehicle is off, the remaining power of the capacitor is consumed through operations of other high voltage components. However, when one of the high voltage component(s) is broken, the remaining power of the capacitor in the high voltage component(s) is not consumed. Therefore, the remaining power remains in the system for a long period of time. If a high voltage line of the system is erroneously touched in this situation (i.e., in the state in which power remains in the capacitor), an accident such as electric shock may occur.